• Nuclear Engineering and Technology
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• 제56권10호
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• pp.4042-4049
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• 2024

A new automatic group structure optimization method based on the perturbation theory was proposed for the few-group structure in two-step nuclear design procedure for VHTR. It applies the sensitivity coefficient of the perturbation theory which includes not only the effect of the cross section on the multiplication factor but also the adjoint weighted reaction rate. The sensitivity coefficient of the fine group for the multiplication factor was calculated and the group boundary for a few-group can be determined so that the summation of the fine group sensitivity for a few-group should be evenly distributed over every few-group. This method was successfully implemented in the ABGO code. VHTR-350 and MiHTR 2D core were used to investigate the performance and applicability of the proposed method. The code generated the new group structures for two cores and the error of the multiplication and reaction rate by the new group structure was compared with the result by the fine group structure. The comparisons indicate that the new group structure by the proposed method can provide the multiplication factor and reaction rates comparable to the existing group structure and more accurate results than the group structure obtained using the Contributon theory.

• Nuclear Engineering and Technology
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• 제45권7호
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• pp.951-960
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• 2013

Energy group structure has a significant effect on the results of multigroup transport calculations. It is known that $UO_2-PuO_2$ (MOX) is a recently developed fuel which consumes recycled plutonium. For such fuel which contains various resonant nuclides, the selection of energy group structure is more crucial comparing to the $UO_2$ fuels. In this paper, in order to improve the accuracy of the integral results in MOX thermal lattices calculated by WIMSD-5B code, a swarm intelligence method is employed to optimize the energy group structure of WIMS library. In this process, the NJOY code system is used to generate the 69 group cross sections of WIMS code for the specified energy structure. In addition, the multiplication factor and spectral indices are compared against the results of continuous energy MCNP-4C code for evaluating the energy group structure. Calculations performed in four different types of $H_2O$ moderated $UO_2-PuO_2$ (MOX) lattices show that the optimized energy structure obtains more accurate results in comparison with the WIMS original structure.

• 대한수학교육학회지:수학교육학연구
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• 제10권1호
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• pp.73-84
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• 2000

This study, after careful consideration on Piaget's structuralism, showed the relationship between Bourbaki's matrix structure of mathematics and Piaget's structure of mathematical thinking. This, studying the basic characters that structure of knowledge should have, pointed out that 'transformation' and to it, too. Also it revealed that group structure is a 'development' are essential typical one which has very important characters not only of mathematical structure but also general structure, and discussed the problem that learners construct the group structure as a mathematical concept.

• Communications for Statistical Applications and Methods
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• 제26권4호
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• pp.359-370
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• 2019

Grouping structures in covariates are often ignored in regression models. Recent statistical developments considering grouping structure shows clear advantages; however, reflecting the grouping structure on the quantile regression model has been relatively rare in the literature. Treating the grouping structure is usually conducted by employing a group penalty. In this work, we explore the idea of group penalty to the quantile regression models. The grouping structure is assumed to be known, which is commonly true for some cases. For example, group of dummy variables transformed from one categorical variable can be regarded as one group of covariates. We examine the group quantile regression models via two real data analyses and simulation studies that reveal the beneficial performance of group quantile regression models to the non-group version methods if there exists grouping structures among variables.

• 디지털융복합연구
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• 제7권3호
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• pp.137-146
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• 2009

This paper aims to propose a framework of content creating group with creativity under new convergence environments. The framework is built based on content concept hierarchy(deep/surface) relating with the creativity of group members. The diversity of group members(potential creativity) decrease and change into creative abilities in one unified view at each content concept hierarchy in time. To do this, three methods of building a creative group(interaction-base, direction-base, hybrid) are proposed. Cooperating processes and operators are designed to promote creative abilities in the content producing group. These cooperations are considering new media convergence industry's job road map(IPTV) and fundamental content attributes(semantic, narrative, discourse). In the framework, creative content is produced with the help of member's cultural openness, media richness and synchronicity, hierachical adaptability on dissimilarity. Deep level creativity of cognitive semiotics on moving image content is composed of psychological, transformational, situational creating abilities in the structure of group members. Designing analogy, metaphor, symbol operators help members to traverse deep structure of content concept hierarchy. Our framework has strong points to relate fundamental content deep structure with structure of content producing group and to induce creativity on cognitive structure of human being.

• Bulletin of the Korean Chemical Society
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• 제32권8호
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• pp.2813-2816
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• 2011

• Korean Journal of Mathematics
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• 제18권1호
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• pp.97-103
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• 2010

It is well known that the group ring K[G] has the nontrivial Jacobson radical if K is a field of characteristic p and G is a finite group of which order is divided by a prime p. This paper is concerned with the structure of the Jacobson radical of such a group ring.

• Nutrition Research and Practice
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• 제8권4호
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• pp.463-468
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• 2014

BACKGROUNDS/OBJECTOVES: Family has an impact on dietary intake of children as a proximal food environment and family structures are changing and becoming more diverse. This study was performed to identify the association between family structure and food group intake of children aged 3-18 years in Korea. SUBJECTS/METHODS: A total of 3,217 children with complete data on variables for household information, dietary intake and sampling weights were obtained from 2010-2011 Korea National Health and Nutrition Examination Survey. Children's family structure was classified into 3 groups (Living with both parents, Living with one parent and Living without parents). To evaluate children's food group intake, scores of individual food groups ('Grains', 'Meat, Fish, Eggs and Beans', 'Vegetables', 'Fruits' and 'Milk and Dairy products') was calculated from percent adherence to the recommended servings of the Korean Food Guidance System (KFGS). 'Food group mean score' was obtained by calculating the average of five food group scores. RESULTS: After adjusting for age, sex, number of family members, and household income, children living with both parents had higher scores in 'Fruits' (P < 0.01), 'Milk and Dairy products' (P < 0.05), and mean score of individual food group score (P < 0.001) compared to children living with one parent. Individual food group scores and mean scores of individual food group scores were associated with different socio-demographic factors in study children. Family structure was associated with 'Fruits,' 'Milk and Dairy products' score and mean scores of food group scores. CONCLUSIONS: These results suggested that different approach might be required to solve nutrition problem in children depending on their family structure and other socio-demographic factors.

• 대한의생명과학회지
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• 제17권4호
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• pp.321-328
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• 2011

This study divided a group of healthy adults aged 20 or older who had a health examination at J General Hospital in Gyeonggi Province into three groups according to the degrees of metabolic syndrome risk factors. They include the normal group (n=58), the pre-metabolic syndrome group (n=112) and the metabolic syndrome group (n=32). They were compared in exercise capacity and cardiac structure and function and impacts of exercise capacity on the cardiac diastolic function. All the groups took echocardiography to have their cardiac structures and functions examined and an exercise stress test to have their exercise capacity measured. The research findings were as follows: There were differences in exercise capacity, cardiac structure, and diastolic heart function among three groups. Between exercise capacity and diastolic heart function was found to be related. It turned out exercise capacity affected the cardiac diastolic functions. In conclusion, there were significant differences in exercise capacity between the normal group and the metabolic syndrome group and in the cardiac structure and function among the normal, metabolic syndrome, and pre-metabolic syndrome group. In addition, METs (metabolic equivalents) and heart rate recovery of exercise capacity turned out to affect cardiac diastolic functions.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(1)
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• pp.117-120
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• 2002

This paper is proposed structure which it sees currently the problem point which it follows in the independent space for work which the members who do a same work from the environment which is to fall tile at distance, therefore the MPLS based VPN necessary to follow, it forms the small-scale group which is closed again with the CUG(Closed User Group) it will be able to own jointly information to present a structure, the individual small-scale groups are closed from outside and the group members are the CUG authentication Process for the security maintenance the model which is possible.